A Neural Signature of Anorexia Nervosa in the Ventral Striatal Reward System
ABSTRACT Animal studies assessing mechanisms of self-starvation under conditions of stress and diet suggest a pivotal role for the mesolimbic reward system in the maintenance of core symptoms in anorexia nervosa, which is corroborated by initial empirical evidence in human studies. The authors examined activity in the ventral striatal system in response to disease-specific stimuli in women with acute anorexia nervosa.
Participants were 14 women with acute anorexia nervosa and 14 matched healthy comparison women who underwent functional magnetic resonance imaging (fMRI) during evaluation of visual stimuli depicting a female body with underweight, normal weight, and overweight canonical whole-body features according to standardized body mass indices. Participants were required to process each stimulus in a self-referring way. Ratings for each weight category were used as the control task.
Behaviorally, women with anorexia nervosa provided significantly higher positive ratings in response to underweight stimuli than in response to normal-weight stimuli, while healthy comparison women showed greater preference for normal-weight stimuli relative to underweight stimuli. Functionally, ventral striatal activity demonstrated a highly significant group-by-stimulus interaction for underweight and normal-weight stimuli. In women with anorexia nervosa, activation was higher during processing of underweight stimuli compared with normal-weight stimuli. The reverse pattern was observed in healthy comparison women.
These findings are consistent with predictions in animal studies of the pivotal role of the human reward system in anorexia nervosa and thus support theories of starvation dependence in maintenance of the disorder.
- SourceAvailable from: Valentina Cardi
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- "For instance, evidence has been found that in the severe and enduring stage of AN brain size is reduced particularly in the cerebellum and mesencephalon . The atypical brain activation to illness relevant cues (for example salient body shape images) is more pronounced in adults than adolescents  . "
ABSTRACT: The aim of this paper is to map the possibility of new treatment approaches for eating disorders. Eating disorders have a protracted trajectory with over 50% of cases developing a severe and enduring stage of illness. Although a good response to family-based interventions occurs in the early phase, once the illness has become severe and enduring there is less of a response to any form of treatment. Neuroprogressive changes brought about by poor nutrition and abnormal eating patterns contribute to this loss of treatment responsivity. We have summarised the profile of symptoms at the various stages of illness and considered new treatments that might be applied. In the enduring stage of illness in addition to problems with body image, food and eating, there are additional problems of low mood, high anxiety and compulsivity and problems in social functioning. This suggests that there are dysfunctions in circuits subsuming reward, punishment, decision-making and social processes. New approaches have been developed targeting these areas. New interventions targeting both the primary and secondary symptoms seen in the enduring stage of eating disorders may improve the response to treatment. Copyright © 2015. Published by Elsevier Inc.Physiology & Behavior 06/2015; DOI:10.1016/j.physbeh.2015.06.007 · 3.03 Impact Factor
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- "In particular it is suggested that initially rewarding behaviour becomes habitual when repeated over time, and eventually becomes insensitive to outcome (Graybiel, 2008). The development of compulsive behaviours may be the result of the aberrant reward processing for disorderrelated stimuli, which has been documented in AN (Cowdrey, Finlayson, & Park, 2013; Cowdrey, Park, Harmer, & McCabe, 2011; Fladung et al., 2010; Park, Godier, & Cowdrey, 2014), and substance dependence (Goldstein & Volkow, 2002). Disorder-related reward may become highly motivationally salient and promote the development of compulsive disorder-related behaviour (Godier & Park, 2014). "
ABSTRACT: The characteristic relentless self-starvation behaviour seen in Anorexia Nervosa (AN) has been described as evidence of compulsivity, with increasing suggestion of transdiagnostic parallels with addictive behaviour. There is a paucity of standardised self-report measures of compulsive behaviour in eating disorders (EDs). Measures that index the concept of compulsive self-starvation in AN are needed to explore the suggested parallels with addictions. With this aim a novel measure of self-starvation was developed (the Self-Starvation Scale, SS). 126 healthy participants, and 78 individuals with experience of AN, completed the new measure along with existing measures of eating disorder symptoms, anxiety and depression. Initial validation in the healthy sample indicated good reliability and construct validity, and incremental validity in predicting eating disorder symptoms. The psychometric properties of the SS scale were replicated in the AN sample. The ability of this scale to predict ED symptoms was particularly strong in individuals currently suffering from AN. These results suggest the SS may be a useful index of compulsive food restriction in AN. The concept of 'starvation dependence' in those with eating disorders, as a parallel with addiction, may be of clinical and theoretical importance. Copyright © 2014 Elsevier Ltd. All rights reserved.Eating Behaviors 12/2014; 17C:10-13. DOI:10.1016/j.eatbeh.2014.12.004 · 1.58 Impact Factor
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- "Secretion of ghrelin, a critical hormone in the complex circuitry responsible for signaling human appetite, is elevated in AN (Germain et al., 2007, 2010; Koyama et al., 2010). Ghrelin signaling is involved in both homeostatic and hedonic pathways, both of which have been shown to be disrupted in individuals with AN (Ellison et al., 1998; Wagner et al., 2007, 2008; Fladung et al., 2010; Gizewski et al., 2010; Frank et al., 2012; Holsen et al., 2012). "
ABSTRACT: Evidence contributing to the understanding of neurobiological mechanisms underlying appetite dysregulation in anorexia nervosa draws heavily on separate lines of research into neuroendocrine and neural circuitry functioning. In particular, studies consistently cite elevated ghrelin and abnormal activation patterns in homeostatic (hypothalamus) and hedonic (striatum, amygdala, insula) regions governing appetite. The current preliminary study examined the interaction of these systems, based on research demonstrating associations between circulating ghrelin levels and activity in these regions in healthy individuals. In a cross-sectional design, we studied 13 women with active anorexia nervosa (AN), 9 women weight-recovered from AN (AN-WR), and 12 healthy-weight control women using a food cue functional magnetic resonance imaging paradigm, with assessment of fasting levels of acylated ghrelin. Healthy-weight control women exhibited significant positive associations between fasting acylated ghrelin and activity in the right amygdala, hippocampus, insula, and orbitofrontal cortex in response to high-calorie foods, associations which were absent in the AN and AN-WR groups. Women with AN-WR demonstrated a negative relationship between ghrelin and activity in the left hippocampus in response to high-calorie foods, while women with AN showed a positive association between ghrelin and activity in the right orbitofrontal cortex in response to low-calorie foods. Findings suggest a breakdown in the interaction between ghrelin signaling and neural activity in relation to reward responsivity in AN, a phenomenon that may be further characterized using pharmacogenetic studies.Psychiatry Research : Neuroimaging 05/2014; 223(2). DOI:10.1016/j.pscychresns.2014.04.015 · 2.83 Impact Factor